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Predicting stage performance of a multi-stage centrifugal compressor using the overall compressor performance characteristic

Dissertation (MEng)--University of Pretoria, 2019.

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Other Authors: Mahmood, Gazi I.
Format: Thesis
Language:English
Published: University of Pretoria 2021
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access_status_str Open Access
author2 Mahmood, Gazi I.
author_browse Mahmood, Gazi I.
author_facet Mahmood, Gazi I.
collection Thesis
dc_rights_str_mv © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MEng)--University of Pretoria, 2019.
format Thesis
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institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:40:40.528Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2021
publishDateRange 2021
publishDateSort 2021
publisher University of Pretoria
publisherStr University of Pretoria
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source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/79588 Predicting stage performance of a multi-stage centrifugal compressor using the overall compressor performance characteristic Mahmood, Gazi I. u28053347@tuks.co.za Van der Spuy, Johan Human, Dirk Cornelius UCTD IGCC stage performance stage stacking Aungier sensitivity analysis similarity principles Engineering, built environment and information technology theses SDG-07 SDG-07: Affordable and clean energy Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Dissertation (MEng)--University of Pretoria, 2019. The reliable operation of Integrally Geared Centrifugal Compressors (IGCCs), used in the coal-fired power generation industry of South Africa, is essential for economic, environmental and safety considerations. However, due to the unavailability of individual stage performance curves, the ability of a compressor owner to identify underperforming stages to maintain these compressors proactively remains limited. This study addresses the stage performance prediction of an IGCC when only the compressor’s overall performance characteristic, in conjunction with the impeller diameters and tip speeds, are known. The study is limited to IGCCs used in the coal-fired power generation industry of South Africa. Based on the limited inputs, two performance modelling methods were considered for this application, namely stage stacking and 1-dimensional modelling. However, stage stacking requires known operating points on each stage performance curve from which the rest of the curve can be extrapolated while 1-dimensional models require detailed stage design information to model stage performance. This study developed a revised stage stacking procedure which in contrast to the traditional stage stacking procedure, does not require a known operating point on each stage’s performance curve, for it assesses the relative stage performance at the compressor’s surge flow rate. The relative maximum pressure ratio of each stage is acquired through the application of similarity principles while a simplified 1-dimensional impeller analysis model is used to assess relative impeller head coefficients. The modelling process was developed based on performance and design data for IGCCs obtained from a compressor manufacturer. Performance data of four IGCCs, consisting of 13 stages, were obtained, including the design data for ten impellers. Hence, the IGCCs satisfy the requirements of geometric and aerodynamic similarity, unveiling a linear relationship between the stage impeller tip speed and maximum pressure ratio. A simplified 1-dimensional performance model was used to assess relative impeller head coefficients. A verification procedure ensured the integrity of the findings of the 1-dimensional model was maintained by comparing the model results to findings obtained using commercial compressor performance modelling software. A sensitivity analysis was conducted on the 1-dimensional performance model to ascertain which input parameters could be scaled as a function of the impeller tip diameter. For the four IGCCs for which data were obtained, the stage-discharge pressure and isentropic efficiency curves were calculated using the developed model. The maximum variation between the measured and calculated pressure and isentropic efficiency curves equaled 8.20% and 10.84%, respectively. The prediction accuracy of the developed modelling procedure is similar to map-based models found in literature and is considered adequate for identifying an underperforming stage. Thus, the developed model could serve as a valuable conditioning monitoring tool for site-based compressor owners. mi2025 Mechanical and Aeronautical Engineering MEng Unrestricted SDG-07: Affordable and clean energy SDG-09: Industry, innovation and infrastructure 2021-04-22T10:33:11Z 2021-04-22T10:33:11Z 2020/09/29 2019 Dissertation Human, DC 2019, Predicting stage performance of a multi-stage centrifugal compressor using the overall compressor performance characteristic, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/79588> S2020 http://hdl.handle.net/2263/79588 en © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle UCTD
IGCC
stage performance
stage stacking
Aungier
sensitivity analysis
similarity principles
Engineering, built environment and information technology theses SDG-07
SDG-07: Affordable and clean energy
Engineering, built environment and information technology theses SDG-09
SDG-09: Industry, innovation and infrastructure
Predicting stage performance of a multi-stage centrifugal compressor using the overall compressor performance characteristic
title Predicting stage performance of a multi-stage centrifugal compressor using the overall compressor performance characteristic
title_full Predicting stage performance of a multi-stage centrifugal compressor using the overall compressor performance characteristic
title_fullStr Predicting stage performance of a multi-stage centrifugal compressor using the overall compressor performance characteristic
title_full_unstemmed Predicting stage performance of a multi-stage centrifugal compressor using the overall compressor performance characteristic
title_short Predicting stage performance of a multi-stage centrifugal compressor using the overall compressor performance characteristic
title_sort predicting stage performance of a multi stage centrifugal compressor using the overall compressor performance characteristic
topic UCTD
IGCC
stage performance
stage stacking
Aungier
sensitivity analysis
similarity principles
Engineering, built environment and information technology theses SDG-07
SDG-07: Affordable and clean energy
Engineering, built environment and information technology theses SDG-09
SDG-09: Industry, innovation and infrastructure
url http://hdl.handle.net/2263/79588